Field of the Invention
The present invention relates to an image forming apparatus, and more particularly to a charge-managing image forming apparatus having a mode in which a user uses the apparatus and a mode in which a service engineer uses the apparatus.
Description of the Related Art
Among image forming apparatuses having copy functions and print functions, there is an image forming apparatus including a charging counter for counting the number of printed sheets to be charged. Such an image forming apparatus has been conventionally known to charge a user based on the number of printed sheets counted by the charging counter.
Japanese Patent Application Laid-Open No. 8-152826 discusses an image forming apparatus including such a charging counter. This image forming apparatus can accurately calculate the number of sheets printed based on an instruction from a user by subtracting the number of sheets printed during maintenance performed by a service engineer from the number of all the printed sheets.
The image forming apparatus discussed in Japanese Patent Application Laid-Open No. 8-152826 does not distinguish between a product printed by the service engineer and a product printed by the user. That is, the image forming apparatus does not distinguish between the printed product not to be charged and the printed product to be charged.
In such a apparatus, in a case where the print method for the service engineer is leaked to the user, there is a possibility that the image forming apparatus may be used improperly. For example, the user pretends to be a service engineer, and performs printing by using the image forming apparatus without a charge. In such a case, the image forming apparatus cannot properly charge the user for the printing.